This invention relates to flowmeters, and more particularly, to a flowmeter pressure relieving device.
Flowmeters are used in a variety of industrial, commercial, medical and military applications to measure the flow of fluids in conduits and pipes. In the USA market, flowmeter design must meet the Compressed Gas Association (CGA) guidelines. The CGA Standard E-7 "Standard for Flowmeters, Pressure Reducing Regulators, Regulator/Flowmeter and Regulator/Flow-Guage Combinations for the Administration Medical Gasses" 1983 sets forth the minimum performance and safety requirements for this type of equipment. Section 7.5 of CGA Standard E-7 specifically deals with flowmeter performance, i.e., minimum burst strength and external lakage of the flowmeter. In essence, these standards require no bursting or fragmentation of the flowmeter when subjected to four times its maximum pressure.
Since the weakest part of the flowmeter is the flowmeter cover, the challenge that has confronted the prior art has been to design a cover which does not burst or fragment when subjected to excessive pressure. Rather than causing bursting or flying cover fragments, the current trend of the prior art is to design a cover so that if rupture occurs, the cover is more likely to bend or deform, without bursting or fragmentation.
Even in those prior art designs where bursting or fragmentation of the cover has been eliminated, once failure occurs, the cover must be replaced in order for the flowmeter to function properly. Depending on the application, obtaining a new flowmeter cover can not only be expensive, but may keep the flowmeter out of service. Unfortunately, this results in costly delays, inconvenience to the user, and unnecessary down time.